at the end of the year i´m sure ps4 sold about 50 million.
ps4 has during year much more games than xbox one and WII U.
in 2 weeks we have uncharted 4, this game probably helps to sell in one month 1 million systems worldwide.
final fantasy XV comes out on september/october.
this game will be exclusive in the asia market consoles, so im sure will be the first game helps to sell near 1 million copies in that market.
remenber dragon quest heroes was released to ps3 and ps4, but this game helped to sell 334,000 units of ps4. so... you can make an idea about what can happen with final fantasy XV.